Differences in macronutrient content of common aquatic macroinvertebrates available as prey for young-of-the-year Scaphirhynchus sturgeons in the lower Missouri River

Nutrient availability in prey items can have important consequences for the growth, reproduction, survival, and recruitment into adulthood of juvenile fish. For young of the year sturgeon, which are highly dependent on macroinvertebrates as prey, knowing the nutritional content across various prey items within their habitats can help managers during habitat restoration. The objective of this study was to test for differences in the macronutrient composition of major invertebrate groups commonly consumed by young of the year sturgeon in the lower Missouri River in the summer, when sturgeon habitat assessments occur. Potential prey vary considerably in size. In addition, there were significant differences in the concentrations of nutrients. The lowest concentration of lipid was found in Odonata (2.36 ± 1.83 mg 100 mg⁻¹; mean ± pooled variance standard error) and the highest was in Diptera (14.49 ± 3.30 mg 100 mg⁻¹). The lowest concentration of protein was found in Ephemeroptera (58.98 ± 1.90 mg 100 mg⁻¹) and the highest concentration was in Trichoptera (70.07 ± 3.26 mg 100 mg⁻¹). Some spatial differences were found in energy derived from protein in Ephemeroptera in the lower Missouri River, but not in energy derived from lipid. Our findings provide useful information that can contribute to adaptive management efforts for sturgeons in the lower Missouri River.